COMPARATIVE PREY SUITABILITY OF OSTRINIA-NUBILALIS EGGS AND ACYRTHOSIPHON-PISUM FOR COLEOMEGILLA-MACULATA

The effects of Ostrinia nubilalis (Hubner) (Lepidoptera: Pyralidae) eg gs and Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), when provi ded as single prey species and in combination, on life history charact eristics of Coleomegilla maculata DeGreer (Coleoptera: Coccinellidae) larvae and adults were quantified. Preimaginal development was not inf luenced by the larval prey regime; development at 26 +/- 1 degrees C w as completed in approximately 13.5 days on O. nubilalis eggs, A. pisum , or A. pisum alternated daily with O. nubilalis eggs. The resulting a dults weighed 13.0, 10.7, and 12.5 mg when reared on O. nubilalis eggs , A. pisum, and A. pisum alternated daily with O. nubilalis eggs, resp ectively. Eighteen percent of the individuals died when reared on A. p isum, 28% died when reared on O. nubilalis eggs, and 22% died when fed A. pisum alternated daily with O. nubilalis eggs. Seven adult diet co mbinations, based on diet regimes of larvae and adults, did not cause significant differences in preoviposition period, interoviposition per iod, and the number of days on which eggs were laid. Total fecundity w as influenced both by larval and adult diet. The diet that resulted in highly fecund females was A. pisum alternated daily with O. nubilalis eggs for larvae and O. nubilalis eggs for adults. Female C. maculata fed 0. nubilalis eggs had the highest intrinsic rate of increase and n et reproductive rate. (C) 1997 Academic Press.